Is it possible to cause an object in Blender v. 2.79b to produce a sound whenever it is struck?
Yes, you can use a cylinder as a string and shape keys to move it up and down:



Create a new Shape Key to move up and down the string:



Then move the string up with Proportional Editing turned on:




Allow the shape key to get a minimum value of -1 to let the string move down:



Then animate the scale of the object:



Bake the sound file to the onto the scale animation curve: 





Next bake the animation curve:



Copy the keyframes from the scale animation to the shape key animation:




Delete the scale, location and rotation keyframes (don't forget to set the scale back to 1.0 in all axes after this):



Finally, add some noise modifier to the animation curve to move the string up and down: